Studies of the interactions of SCN with the soybean aphid


Investigators: Gregory L. Tylka, Matthew E. O’Neal, Felicitas Avendano
Funding: Iowa Soybean Association

The soybean aphid, Aphis glycines, was first discovered feeding on soybeans in Iowa and other Midwestern states in 2000. Since then, it has spread throughout the state and region. Currently, soybean aphids are found in every county in Iowa and the insect has become a serious yield-reducing pest of soybeans in the state.

Because both SCN and soybean aphid are widespread in Iowa, knowledge of how these two soybean pests affect each other and interact to affect the soybean crop is needed. It is possible that soybean aphid infestations and resulting yield loss will be intensified by infection of host soybean plants with SCN.

Field microplot and growth chamber experiments began in 2005 to determine how SCN and the soybean aphid affect each other, and how the interaction affects soybean growth and yield. Key findings of the research include:

  • Reproduction of soybean aphids is similar on SCN-infected and uninfected soybeans.
  • Soybean aphids do not have a preference for SCN-infected or uninfected soybean plants.
  • Yield loss occurred at a lower population density of soybean aphid on plants infected with SCN compared to those not infected with the nematode.

This research will continue through 2008.

Field microplots used to study the interaction of SCN with the soybean aphidMesh cages covering individual plants growing in microplots; the cages exclude all insects other than the soybean aphids added to the plants

Mesh cages covering individual plants growing in pots in a growth chamber experiment; the cages exclude all insects other than the soybean aphids added to the plants  	Click on the image to view a one-page information sheet (mini poster) in pdf format.

The rate of soybean aphid population growth on five soybean varieties in microplots was similar with SCN or without SCN